The Descent of Man, and Selection in Relation to Sex

Charles Darwin’s *The Descent of Man, and Selection in Relation to Sex*, published in 1871, applies his evolutionary theory specifically to humans and lays out his concept of sexual selection—a kind of biological adaptation that works alongside natural selection but is distinct from it. Darwin used “descent” to mean a direct line of ancestors. The book covers a wide range of topics: evolutionary psychology, evolutionary ethics, evolutionary musicology, racial differences, sex differences, the leading role women play in choosing mates, and what evolutionary theory means for society. **Publication**

As Darwin wrote, he sent chapters to his daughter Henrietta for editing, to prevent anyone from drawing harmful conclusions, and also consulted his wife Emma. The zoological illustrator T. W. Wood, who had also drawn for Wallace’s *The Malay Archipelago* (1869), created many of the book’s figures. Darwin sent the corrected proofs to his publisher John Murray on 15 January 1871, and the work came out on 24 February 1871 as two 450-page volumes. Darwin insisted these formed one complete, coherent work, priced at £1/4/–. Within three weeks, a reprint was ordered, and by the end of March 1871, 4,500 copies were in print, earning Darwin nearly £1,500. Darwin’s name drove demand, but the ideas were already familiar. “Everybody is talking about it without being shocked,” he noted, which he took as “proof of the increasing liberality of England.”

**Editions and Reprints**

Darwin and some of his children edited many revised editions, some heavily. In late 1873, Darwin began work on a new edition of *Descent*. He first offered the task to Wallace, but when Emma found out, she insisted their son George take it on, forcing Darwin to write an apologetic letter to Wallace. Thomas Henry Huxley helped update the section on ape-brain inheritance, which Huxley felt “pounds the enemy into a jelly... though none but anatomists” would notice. The manuscript was finished in April 1874 and published on 13 November that year. This edition has been the one most commonly reprinted since Darwin’s death and remains so today. **Content**

**Part I: The Evolution of Man**

*Evolution of Physical Traits*

In the introduction, Darwin states the book’s purpose: “The sole object of this work is to consider, firstly, whether man, like every other species, is descended from some pre-existing form; secondly, the manner of his development; and thirdly, the value of the differences between the so-called races of man.” To argue for human evolution, Darwin highlights how similar humans are to other animals. He starts with anatomical likenesses—body structure, embryology, and “rudimentary organs” that were probably useful in one of man’s “pre-existing” forms—then moves on to argue for mental similarities. *Evolution of Mental Traits*

Drawing on the work of his cousin Francis Galton, Darwin claims that human character and mental traits are inherited just like physical ones, and he rejects the mind/body distinction for evolutionary purposes. He then offers evidence of similar mental powers in certain animals, especially apes, monkeys, and dogs, using them as analogies for love, cleverness, religion, kindness, and altruism. He concludes: “Nevertheless the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.” He also looks at the behavior of “savages” to show how many aspects of Victorian society appear in more primitive forms. Specifically, Darwin argues that moral and social instincts are evolved, comparing human religion to fetishism in “savages” and his dog’s confusion over whether a wind-blown parasol was alive. He also contends that all civilizations arose from barbarism and rejects the idea that barbarism is a “fall from grace,” as many of his contemporaries believed. *Natural Selection and Civilised Society*

In this section, Darwin addresses what would later be called social Darwinism and eugenics. He notes, as Alfred Russel Wallace and Galton had, that natural selection no longer seemed to act on civilized communities the way it does on other animals: “With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race; but excepting in the case of man himself, hardly any one is so ignorant as to allow his worst animals to breed.” He adds that the urge to help the helpless is mainly a byproduct of the instinct of sympathy, originally part of social instincts but later made more tender and widespread.